SMALL ISSUE: Nets forward Gerald Wallace (above, guarding the Raptors’ Kyle Lowry) missed Monday’s game because of a sprained left ankle, but his return would solidify Brooklyn’s defense against the smaller Heat lineup. Photo: NBAE/Getty Images

MIAMI — The Nets’ struggles against small lineups cropped up once again Monday night, when the Timberwolves went small and stormed back from a 22-point deficit to stun the Nets and hand them their first loss in Brooklyn.

But any issues Timberwolves backup power forward Dante Cunningham caused the Nets down the stretch of Monday’s 107-96 loss will be magnified several times over when the Nets face LeBron James and the defending champion Heat tonight at AmericanAirlines Arena.

“You have to have a short memory and put this behind us,” Joe Johnson said following Monday’s loss. “We’ve got to go try to bounce back and get one.”

The Nets’ chances of getting an upset win in Miami tonight will go up significantly if starting small forward Gerald Wallace can return from a sprained left ankle that held him out of Monday’s loss.

Although he may not get as much publicity as Deron Williams, Johnson or Brook Lopez, Wallace’s versatility arguably makes him the Nets’ most valuable player. When Wallace, who is listed as day-to-day, is in the lineup, the Nets have the ability to match up with smaller lineups featuring either undersized power forwards or small forwards masquerading at the four spot — as James has been doing for the Heat.

But when they are without Wallace, as they were Monday night, the Nets are left with few good options to turn to when teams go small and speed up the game, as the Timberwolves did to great effect in outscoring the Nets 32-10 in the fourth quarter.

“I know we’re obviously alluding to our next game, but when Gerald moves over to the four, that gives us so many more options offensively and defensively,” Nets coach Avery Johnson said. “It helps with our pick-and-roll coverage … here’s a guy that can kind of be a point forward for our team. Now we can get Deron and C.J. [Watson] working off some screens and Joe … it spreads the floor more for Brook to operate.

“So when you don’t have that, it can be a challenge, but we’ll have to adjust.”

But adjusting to James is a near impossible task for any team — let alone one that could potentially be missing its best defender and the only one really capable of handling the assignment of trying to limit the damage James can cause.

“You’ve got to have somebody to try to slow down guys like that,” Williams said. “It’s impossible to stop him, but you try to slow him down and make him work on both ends of the floor, so they tire out a little bit. That’s all you can really do against guys like LeBron.”

When you combine James’ strength and athleticism at power forward with the talents of co-stars Chris Bosh and Dwyane Wade and spot-up shooters like Shane Battier and Ray Allen, it becomes an even more difficult proposition to cool off the Heat.

But after a stunning and disappointing loss — their first as a Brooklyn team and first inside the brand-new Barclays Center — to an undermanned Timberwolves team, the Nets have to try to come up with a way, with or without Wallace, to combat Miami’s explosiveness and get a win.

“I expect them to respond,” Avery Johnson said. “I would expect them to be upset and disappointed. We’ve got great guys on our team. Historically here, we’ve always had problems with small lineups. And, you saw again tonight, they went small at four and it kind of put us in a bind.

“Those are situations why we feel so strongly about Wallace. And, with him not being here, we’ve got to come up with a solution and as a staff to figure out what to do in those situations.”